The purpose of this contract is to conduct studies, which will help the National Toxicology Program (NTP) in the toxicologic characterization associated with short-term exposures to a variety of chemicals. The studies are designed to identify possible target organs of toxicity and differences in sensitivity between sexes and species of animals and dose-response relationships, and possible mechanism of toxicity. Data from prechronic studies will be used by the National Toxicology Program to characterize and publicize the toxicity of chemicals studied and for establishment of dose levels of chemicals selected for subsequent long-term carcinogenecity studies. Studies conducted during the year were (1) the Prechronic (13-week) Toxicity Study of the Serotype 5 Adeno-associated Viral Vector rAAV5SCTLA4:Ig in Balb/c Mice (2) Prechronic Toxicity Evaluation of 1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium chloride, 1-butyl-1-methylpyrrolidinium chloride, and N-butylpyridinium chloride